In the fibre-spinning production of the present-day textile industry the most promising trend is the employment of ringless spinning apparatus. Such apparatus can be generally categorized into two classes, the first class including apparatus wherein the working member is in the form of a rotary spinning chamber, while the second class includes apparatus where a twisting member in the form of a rotatable rotor acts as the work-performing member.
At present, there are commonly known ringless spinning arrangements wherein the spinning member includes a rotatable rotor (cf. U.S. Pat. No. 3,877,211; Cl. 57/58.89; dated April, 1975). The rotor includes a disc having a central duct formed therethrough for the passage of fibres and a sleeve arranged axially of the rotatable rotor, underlying the disc and being resiliently urged thereto. The disc has a supporting surface adapted to receive fibres thereon and to shape them into a thread, with the rotor rotating. Fibres are retained on the surface of the disc owing to the mechanical action thereupon of projections provided on the surface of the disc.
However, since there is no elastic clamping action exerted on the thread being formed, the device of the prior art displays a tendency of producing loose yarn with low physical and mechanical properties. Such yarn is practically unfit for further utilization.
The above drawback can be eliminated by employing a twisting member of the kind disclosed in the SU Inventor's Certificate No. 225,049; Int. Cl. D 01 H, published on Aug. 12, 1968 which we consider the closest prototype of the present invention. This twisting member comprises a rotor including a disc with a central through-going duct for the passage of fibres, a sleeve arranged axially of the disc, underlying the latter and being resiliently urged toward the disc. Interposed between the disc and the sleeve is a spherical element, or ball defining with the sleeve a means for resiliently clamping the thread being formed.
However, twisting members of the above type have proved to show a high thread breakage rate. This can be explained by the fact that the resilient clamping action exerted by the ball takes place in two zones of which the first one is between the disc and the ball, and the second one is between the ball and the sleeve.
The first zone of clamping is one occupied by separate fibres with little or no interconnection therebetween, whereas in the second zone the fibres are already twisted into a thread and exhibit considerable adhesion to one another.
When either large particles of foreign matter or strands of fibres become situated in the first clamping zone, the fibres are held fast, and, consequently, their access to the second clamping zone is halted, whereby the fibres that are already in the second zone are being torn apart under the action of the forces of tension, while there is no in-feed of fibres from the first clamping zone.